LASS5 Is a Bona Fide Dihydroceramide Synthase That Selectively Utilizes Palmitoyl-CoA as Acyl Donor*

By S. Lahiri, A. Futerman. 2005

130 citations recorded by the source corpus.

We demonstrated recently (Riebeling, C., Allegood, J.C., Wang, E., Merrill, A. H. Jr., and Futerman, A. H. (2003) J. Biol. Chem. 278, 43452–43459) that upon over-expression in human embryonic kidney cells, longevity assurance gene homolog 5 (LASS5, previously named TRH4) elevates the synthesis of (dihydro)ceramides selectively enriched in palmitic acid. To determine whether LASS5 is a bona fide dihydroceramide synthase or, alternatively, whether it modifies an endogenous dihydroceramide synthase, we over-expressed LASS5 with a hemagglutinin (HA) tag at the C terminus, solubilized it using digitonin, and purified it by immunoprecipitation. Solubilized LASS5-HA displays the same fatty acid selectivity as the membrane-bound enzyme. After elution from agarose beads, only one band could be detected by SDS-PAGE, and its identity was confirmed to be LASS5 by mass spectrometry. Dihydroceramide synthase activity of the eluted LASS5-HA protein was totally dependent on exogenously added phospholipids. Moreover, eluted LASS5-HA was highly selective toward palmitoyl-CoA as acyl donor and was inhibited by the (dihydro)ceramide synthase inhibitor, fumonisin B1. This study identifies LASS5 as a genuine dihydroceramide synthase and demonstrates that mammalian dihydroceramide synthases do not require additional subunits for their activity.

Subfields: Biochemistry, Molecular Biology

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biochemistry

In Molecular Biology

Citations in the corpus

Mammalian Ceramide Synthases (2010, background): “CerS5 was also the first mammalian CerS to be purified (35).”
(Dihydro)ceramide Synthase 1–Regulated Sensitivity to Cisplatin Is Associated with the Activation of p38 Mitogen-Activated Protein Kinase and Is Abrogated by Sphingosine Kinase 1 (2007, methodology): “blotting with anti-hemagglutinin antibody (20).”
Antiapoptotic roles of ceramide‐synthase‐6‐generated C16‐ceramide via selective regulation of the ATF6/ CHOP arm of ER‐stress‐response pathways (2010, unknown): “To determine the roles of dh-C18and dh-C16-ceramides generated by CerS1 and CerS6, respectively (9, 31), in the regulation of cell death, the expression of CerS1 and CerS6 was down-regulated using siRNAs.”
Differential expression of (dihydro)ceramide synthases in mouse brain: oligodendrocyte-specific expression of CerS2/Lass2 (2008, unknown): “dihydroceramides containing C18 or shorter fatty acids in vitro and vivo in mammalian cells (Lahiri and Futerman 2005; Mizutani et al. 2005).”
Role of human longevity assurance gene 1 and C18-ceramide in chemotherapy-induced cell death in human head and neck squamous cell carcinomas (2007, background): “The mammalian homologues of yeast LAG1 were later identified in human, Caenorhabditis elegans (19), and mouse (17), and recent independent studies have shown specific functions of mouse LASS1, LASS5, and LASS6 in the specific generation of C18-, C16- and C14/C16ceramides, respectively (17, 30, 31).”